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I attempted a coolant flush for the first time on my 1989 C4 Vette today. I was able to disassemble and reassemble the fan shroud to clean debris, and remove the radiator and flush it. My coolant has been rusty looking so I followed the instructions to remove the knock sensor in order to drain the fluid from the engine block. I had trouble trying to remove the knock sensor and damaged it. No biggie I went a got a new one. However while trying the remove the knock sensor I rounded it. It’s in there really tight! I was using a 7/8 head which I believe is the correct size. Any ideas on how I can get the this thing out? Thanks in advance for any advice. This forums a great resource for new corvette owners.
From: Liliha Bakery stuffing my face with coco puffs!
Had one within arms reach and so was my micrometer and yes .875" or 7/8". Suppose it's beyond try a six point socket instead of 12. There's high torque sockets not sure that's what they are called but flank drive socket that place the emphasis on the flats and less on the points of the hex. Perhaps a lugnut remover might work, too.
Last edited by stew86MCSS396; Sep 5, 2020 at 11:40 PM.
Ok, so if I was to go to the tool store I would ask for a six point socket flank drive in 7/8 size? This is pretty new to me, I am learning as I go. That being said I want to make sure I ask for the right things.
A lugnut remover is actually a great idea! There isn't much space to work with near the knock sensor so I'll try the different styles of lugnut removers. Also there is that plastic looking piece that sticks out of the knock sensor so it will have to be somewhat of a longer socket.
The outside will accommodate a 7/8 socket or wrench. On the inside next to the block there is a 9/16 sized hex. If yours doesn't have it, a pipe wrench or vice grips will work.
From: Liliha Bakery stuffing my face with coco puffs!
The one I measured is threaded all the way up to the body of the sensor. Just wanted to add when it's time to install the new one, been told that over torquing the KS can either damage it or make it over sensitive so be sure to install to it's proper torque of 14 ft-lbs.
Still no luck. I ordered a set of sockets for impacted bolts on Amazon. Hopefully that will be able to get the knock sensor out. If not I might have to just gorilla glue a 7/8 socket to the knock sensor and remove it that way. I know it sounds crazy, but I have done this in the past with stubborn rounded bolts. It's worked.
Rounded Knock Sensor Bolt
so be sure to install to it's proper torque of 14 ft-lbs.
